The purpose of this study is to assess the efficacy of tryptophan vs. placebo, and voucher
payments vs. a control condition, in the treatment of cocaine dependence.
This clinical trial uses a 2 by 2 design to compare tryptophan to placebo, and voucher
incentives vs. a control condition, in the outpatient treatment of cocaine dependence- using
a relapse prevention model of treatment intervention.
- Cocaine dependent
- Physically dependent on drugs of abuse other than cocaine
- Significant medical or psychiatric illness (besides substance abuse disorder)